Description of the effect of the practical management in the characterization of « terroir effect »

Oxidation processes constitute a main problem in winemaking. Oxidation result in color browning and varietal aroma loss, which are key attributes of wine organoleptic quality [1]. Despite the mechanisms involved in wine oxidation have been extensively reviewed [2], the protection of wine against oxidative spoilage remains one of the main goals of winemaking. SO2 is one of the most efficient wine antioxidants used to prevent oxidation and microbial spoilage. However, intolerances caused by SO2 have led to the reduction of its concentration in wines.

Vineyard exposure to smoke can lead to grapes and wine which exhibit objectionable smoky and ashy aromas and flavours, more commonly known as ‘smoke taint’ [1, 2]. In the last decade, significant bushfires have occurred around the world, including near wine regions in Australia, Canada, South Africa and the USA, as a consequence of the warmer, drier conditions associated with climate change. Considerable research has subsequently been undertaken to determine the chemical, sensory and physiological consequences of grapevine exposure to smoke. The sensory attributes associated with smoke-tainted wine have been linked to the presence of several smoke-derived volatile phenols, such as guaiacols, syringols and cresols [2].

Measurement of carbon isotope discrimination in berry juice sugars at maturity (δ13C) provides an integrated assessment of water use efficiency (WUE) during the period of berry ripening, and when collected over multiple seasons can be used as an indication of drought stress response. Berry juice δ13C measurements were carried out on 48 different varieties planted in a common garden experiment in Bordeaux, France from 2014 through 2021 and were paired with midday and predawn leaf water potential measurements on the same vines in a subset of six varieties. The aim was to discriminate a large panel of varieties based on their stomatal behaviour and potentially identify hydraulic traits characterizing drought tolerance by comparing δ13C and hydroscapes (the visualisation of plant stomatal behaviour as a response to predawn water potential). Cluster analysis found that δ13C values are likely affected by the differing phenology of each variety, resulting in berry ripening of different varieties taking place under different stress conditions within the same year. We accounted for these phenological differences and found that cluster analysis based on specific δ13C metrics created a classification of varieties that corresponds well to our current empirical understanding of their relative drought tolerances. In addition, we analysed the water potential regulation of the subset of six varieties (using the hydroscape approach) and found that it was well correlated with some δ13C metrics. Surprisingly, a variety’s water potential regulation (specifically its minimum critical leaf water potential under water deficit) was strongly correlated to δ13C values under well-watered conditions, suggesting that base WUE may have a stronger impact on drought tolerance than WUE under water deficit. These results give strong insights on the innate WUE of a very large panel of varieties and suggest that studies of drought tolerance should include traits expressed under non-limiting conditions.

Tutte le cantine possono aprirsi al pubblico? Evidentemente si, nessuno può impedire ad un produttore di accogliere i turisti.
Tutte le cantine possono far parte delle Strade del vino? No, perché la Strada del vino mette in gioco la reputazione della denominazione di origine alla quale è legata e le possibilità di sviluppo economico di un intero territorio.

Aim: Climate is arguably one of the most important factors determining the quality of wine from any given grapevine variety. High rainfall during spring can promote growth of the vines but increases the risk of fungal disease, while vineyard operations can be disrupted, as machinery may be prevented from getting in the vineyard owing to muddy soils.